Ingredients:

  • 2 cups all-purpose flour
  • 1 cup granulated sugar
  • 1 tsp baking powder
  • 2 tsp ground cinnamon
  • 1/2 tsp salt
  • 1/2 cup unsalted butter, softened
  • 2 large eggs, room temperature
  • 1/2 cup full fat sour cream
  • 1 tsp vanilla extract
  • 3 cups peeled and diced Granny Smith or Honeycrisp apples
  • 3 tbsp cold unsalted butter, cubed
  • 1/4 cup packed brown sugar
  • 1 tsp ground cinnamon

Instructions:

  1. Preheat oven to 350°F (175°C). Grease a 9x9 inch square baking pan and line it with parchment paper.
  2. In a large bowl, beat the softened butter and granulated sugar together until light and fluffy.
  3. Whisk in the eggs one at a time, then stir in the vanilla extract and sour cream until smooth.
  4. Sift in the flour, baking powder, cinnamon, and salt. Fold gently with a spatula until no white streaks remain.
  5. Gently fold in the diced apples, ensuring they are evenly distributed throughout the batter.
  6. Pour the batter into the prepared pan and smooth the top with a spatula.
  7. In a small bowl, mash the cold cubed butter, brown sugar, and cinnamon together with a fork until the mixture resembles wet sand.
  8. Sprinkle the crumble mixture evenly over the raw batter.
  9. Bake for 40–50 minutes until the top is deep golden mahogany and a toothpick inserted in the center comes out clean or with a few moist crumbs.